Is it possible to approximate the thickness from this data?

[laramman2]

The thickness of an unexposed filter is 40um and a diameter of 46.2mm. I have an exposed air sampling filter with a mass concentration of the particulate (from gravimetric analysis) 20.1ug/m³. If I assume that the particulates are uniformly distributed in the surface of the filter, is it possible to approximate the thickness? Thank you very much. :)

 

[CWatters]

I can't see how unless you know the mass of the sample. Then you can work out the volume using the density. Then you can work out the thickness assuming that volume is spread over the area of the filter.